Pictures: NFL playoffs kick off with wild-card games

Tom Pennington, Getty Images

Quarterback Matthew Stafford #9 of the Detroit Lions fumbles the ball after being sacked by defensive end Demarcus Lawrence #90 of the Dallas Cowboys in the fourth quarter during a NFC Wild Card Playoff game at AT&T Stadium on January 4, 2015 in Arlington, Texas.

Quarterback Matthew Stafford #9 of the Detroit Lions fumbles the ball after being sacked by defensive end Demarcus Lawrence #90 of the Dallas Cowboys in the fourth quarter during a NFC Wild Card Playoff game at AT&T Stadium on January 4, 2015 in Arlington, Texas. (Tom Pennington, Getty Images)